Cataract surgery for the developing world Geoffrey Tabin a, Michael Chen b and Ladan Espandar a

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1 Cataract surgery for the developing world Geoffrey Tabin a, Michael Chen b and Ladan Espandar a a John A. Moran Eye Center, University of Utah, Salt Lake City, Utah and b David Geffen School of Medicine at UCLA, Los Angeles, California, USA Correspondence to Geoffrey Tabin, MD, John A. Moran Eye Center, 65 North Medical Dr, Salt Lake City, UT 84132, USA Tel: ; fax: ; Geoffrey.Tabin@hsc.utah.edu Current Opinion in Ophthalmology 2008, 19:55 59 Purpose of review To review surveys published within the last year concerning the prevalence of cataract blindness, rates of cataract surgical coverage and visual outcomes of cataract surgery in various developing countries, and to review recent studies that compare the different cataract surgical techniques used in developing countries. Recent findings Up to 75% of blindness (visual acuity below 20/400) is due to cataract. Cataract remains the most common treatable cause of blindness. Reported cataract surgical coverage is low, and visual outcomes are poor and necessitate improvement. Phacoemulsification is the preferred technique for cataract surgery in developed countries, but large-scale implementation in developing countries may prove to be a challenge. An alternative surgical technique, manual sutureless small incision extracapsular cataract surgery, has been increasing in popularity, as the technique has been shown to yield similar surgical outcomes as phacoemulsification. Summary Treating cataract blindness worldwide continues to be a formidable challenge. Significant barriers include cost, lack of population awareness, shortage of trained personnel and poor surgical outcomes. Both phacoemulsification and manual small incision extracapsular cataract surgery achieve excellent visual outcomes with low complication rates, but manual small incision extracapsular cataract surgery is significantly faster, less expensive and requires less technology. Therefore, manual small incision extracapsular cataract surgery may be the preferred technique for cataract surgery in the developing world. Keywords cataract blindness, cataract surgery, developing countries, manual sutureless small incision cataract surgery Curr Opin Ophthalmol 19:55 59 ß 2008 Wolters Kluwer Health Lippincott Williams & Wilkins Introduction Cataract blindness poses one of the greatest public health challenges of the 21st century. Cataract is the leading cause of blindness worldwide, accounting for nearly half (47.8%) of all cases of blindness [1]. According to the World Health Organization (WHO), an estimated 20 million people worldwide are blind from bilateral cataracts [2]. It is estimated that over 90% of the world s visually impaired live in developing countries [3]. In these countries, blindness is associated with considerable disability and excess mortality, resulting in large economic and social consequences [4]. In 2002, the WHO estimated that blindness affected 37 million people globally [1]. If efforts are not increased to treat avoidable blindness worldwide, this number is projected to increase to 76 million by the year 2020 [4]. To address this issue of increasing blindness, in 1999 the WHO and the International Agency for the Prevention of Blindness launched a global initiative called VISION 2020: the Right to Sight to eliminate avoidable blindness by the year Here, the aims of this article are to review the surveys published within the last year concerning the prevalence of cataract blindness, rates of cataract surgical coverage and visual outcomes of cataract surgery in various developing countries, and to review recent studies that compare the advantages and disadvantages of different cataract surgical techniques that are used in developing countries. Given the implications of these studies, we are convinced that it is possible to develop high-quality, high-volume, low-cost programs for relieving cataract blindness. Prevalence of cataract blindness The WHO defines blindness as presenting visual acuity below 20/400 in the better eye with available correction, severe visual impairment as presenting visual acuity of 20/400 or above, but below 20/200 with available correction, and visual impairment as presenting visual acuity of ß 2008 Wolters Kluwer Health Lippincott Williams & Wilkins

2 56 Cataract surgery and lens implantation Table 1 Prevalence of blindness (by World Health Organization standards unless otherwise noted) in underdeveloped countries as reported in national and regional surveys Country Region Number of persons examined Age of study population (years) Prevalence of blindness [% (95% confidence interval)] Blindness due to cataract (%) Pakistan National > ( ) 51.5 [7 ] India Tamil Nadu 3924 > ( ) [8] Nepal Gandaki Zone 5002 > ( ) (VA < 20/200) 74.2 [9] Myanmar Meiktila District 2076 > ( ) 53 [10] Papua New Guinea National 1174 > ( ) 73.2 [11] Philippines Antique District 3177 > ( ) 63 [12] Philippines Negros Island 2774 > ( ) 54 [12] Timor-Leste Dili and Bobonaro 1414 > (NA) (VA < 20/200) 76.1 [13] Botswana National 2127 > ( ) 46.9 [14] Cameroon Limbe Urban Area, 2215 > ( ) 21 [15] South West Province Cameroon Muyuka, South West Province 1787 > ( ) 62.1 [16] Cape Verde Islands National 3374 all ages 0.8 ( ) 57.7 [17] Kenya Nakaru district 3503 > ( ) 42.0 [18] Nairobi Kibera slums 1438 NA 0.6 ( ) 37.5 [19] Nigeria Imesi-Ile, Osun State NA 44.4 [20] Nigeria Ozoro, Delta State 815 > (4.6 8) 60 [21] Rwanda Western Province 2206 > ( ) 65 [22] Sudan Mankien Payam 2499 >5 4.1 ( ) 41.2 [23] NA, not applicable; VA, visual acuity. 20/200 or above, but below 20/60 with available correction [5]. Several national and regional surveys regarding visual impairment from Asia and Africa were published within the last year. By the WHO definition of blindness, the prevalence of blindness ranged from % of the study populations. The WHO considers blindness to be a public health problem when the prevalence of blindness in the general population exceeds 1.0% [6]. In most of these surveys, cataract was the most common cause of blindness, accounting for almost 75% of cases of blindness in several surveys. See Table 1. Cataract surgical coverage Given the high prevalence of treatable blindness due to cataracts in developing countries, it is important to assess the proportion of individuals with blinding cataracts who undergo cataract surgery. Cataract surgical coverage (CSC) can serve as a marker of the availability of eye care services and is defined as the percentage of individuals (or eyes) with operable cataracts that have undergone cataract surgery. Operable cataract can be defined at different visual acuity cutoffs [24] and thus the CSC can vary. As apparent from the CSC values in various developing countries reported within the past year (Table 2), the CSC is usually higher with worsening visual acuity. Inadequate coverage may be due to various barriers to patient care. In the survey conducted in Pakistan, those who remained blind from operable cataracts were asked why they did not receive cataract surgery; 76.1% identified cost and 11.5% identified lack of awareness [25 ]. Similar reasons were reported in the surveys conducted in the Philippines, Botswana, Cameroon and Kenya [12,14 16,18]. Another reason reported in the surveys conducted in Botswana and Kenya was lack of escort [14,18]. In Timor-Leste, when those who had previously undergone surgery or had at least one vision impaired eye (visual acuity below 20/60) were asked what price they were willing or able to pay for cataract surgery, 94% were unwilling and/or unable to pay more than US$10 [13]. Table 2 Cataract surgical coverage in underdeveloped countries as reported in national and regional surveys Cataract surgical Country Region Visual acuity coverage (individuals) (%) Pakistan National <20/400; <20/200; <20/ ; 69.3; 43.7 [25 ] Nepal Gandaki Zone <20/ [9] Cameroon Limbe Urban Area, South West Province <20/400: <20/200 80; 71 [15] Cameroon Muyuka, South West Province <20/400; <20/200 55; 64.3 [16] Botswana National <20/ [14] Kenya Nakaru district <20/400; <20/200 78; 48.3 [18] Rwanda Western Province <20/400; <20/200; <20/ ; 42.6; 21.4 [22] Timor-Leste Dili and Bobonaro <20/ [13] Philippines Negros Island <20/400; <20/200; <20/ ; 57.9; 27.0 [12] Philippines Antique District <20/400; <20/200; <20/ ; 50.8; 32.1 [12]

3 The developing world Tabin et al. 57 Reported visual outcomes from population surveys Relieving cataract blindness not only involves sufficient surgical coverage, but also good surgical outcomes. Growing concern exists over the outcomes of cataract surgery in developing countries. The surgical outcomes reported in recent surveys (Table 3) are noticeably suboptimal when compared to consolidated data from the US, Canada, Denmark and Spain [27]. In these four developed countries, 92% of operated eyes achieved a postoperative visual acuity of 20/60 or above, 6% 20/200 or above and below 20/60, and 2% below 20/200. Of note, with the exception of the survey conducted in Pakistan, the particular cataract surgery techniques utilized [i.e. intracapsular cataract extraction (ICCE), conventional extracapsular cataract extraction (ECCE), phacoemulsification and manual sutureless small incision cataract surgery (SICS)] were not specified, and thus these data cannot be used to evaluate and compare the efficacy of these surgical techniques. Surveys in Pakistan and in the Nakaru district, Kenya, attributed poor postoperative visual acuity to refractive error (53.4 and 33.9%), surgical complications (21.4 and 30.4%) and concurrent eye disease (23.5 and 35.7%) [18,26 ]. Posterior capsular opacification was the most common postoperative complication and due to the unavailability of the Nd:YAG laser, only 0.98% of these patients received YAG capsulotomy [26 ]. Good postoperative visual outcomes were associated with the use of intraocular lenses (IOLs) [12,15,18,22,26 ]. Poor postoperative visual outcomes were associated with ICCE, surgery performed at an eye camp or government hospital, rural dwelling, female gender and illiteracy [26 ]. The difference between uncorrected visual acuity and best corrected visual acuity in several studies brings attention to the fact that residual refractive error is a major barrier to successful outcomes and highlights the importance of adequate follow-up care. The preferred surgical technique is one that minimizes the need for postoperative refractive correction. Comparisons of different approaches to cataract surgery Several studies have brought attention to the advantages and disadvantages of various surgical approaches to cataract surgery in developing countries. Throughout the first four decades of the 20th century, ICCE was the predominant form of lens removal worldwide [28]. As patients remain aphakic after ICCE, aphakic spectacles must be worn for optical correction [29]. Aphakic spectacles, if the patient receives and uses them, pose obvious disadvantages such as image magnification, restricted visual fields, poor coordination and physical discomfort. ECCE with the implantation of an IOL became the preferred method of cataract surgery in the 1980s and today most surgeons in developing countries have been trained in this technique. Despite the better visual outcomes of ECCE over ICCE, ICCE is still a technique commonly practiced in developing countries and continues to outnumber ECCE in countries such as Pakistan (61.5 vs. 33.9%) [26,30]. Phacoemulsification is the predominant surgical technique employed in developed countries, as studies have suggested that phacoemulsification gives better visual outcomes than ECCE [31,32]. This is attributed in part to less postoperative astigmatism due to the lack of sutures and smaller size of incision (phacoemulsification around 3 mm, ECCE around 12 mm) [33]. Phacoemulsification, however, is difficult to employ in high volume in developing countries as the technology requires costly machinery and consumables, a permanent and reliable source of electricity, regular maintenance, and specially trained surgeons and support staff. Phacoemulsification can also potentially lead to more serious complications when used to remove extremely dense cataracts commonly encountered in developing countries [31]. Given these challenges, manual sutureless SICS has been the technique increasingly employed in developing countries. Manual SICS is comparable to phacoemulsification in achieving excellent visual outcomes with low Table 3 Postoperative visual acuities as reported in national and regional surveys Country Region Number of eyes operated Visual acuities With no correction or available correction (%) With best correction (%) Pakistan National /60; 20/200, <20/60; <20/ ; 35.3; ; 27.5; 22.1 [26 ] Cameroon Limbe Urban Area, 26 20/60; 20/200, <20/60; <20/200 23; 19; 57 NA [15] South West Province Cameroon Muyuka, South West 28 20/60; 20/200, <20/60; <20/200 25; 10.7; 64.3 NA [16] Province Botswana National 148 <20/200 NA 37 [14] Kenya Nakaru district /60; 20/200, <20/60; <20/ ; 19.8; ; 14.4; 22.1 [18] Rwanda Western Province 29 20/60; 20/200, <20/60; <20/200 24; 35; 41 55; 14; 31 [22] Philippines Negros Island /60; 20/200, <20/60; <20/200 68; 17; 23 70; 15; 15 [12] Philippines Antique District /60; 20/200, <20/60; <20/200 70; 18; 13 79; 13; 8 [12] NA, not applicable.

4 58 Cataract surgery and lens implantation complication rates, but is significantly faster, less expensive and requires less technology [33,34,35,36]. Gogate et al. [33] compared phacoemulsification with manual SICS in a randomized controlled trial of 400 eyes in India and concluded that the techniques were comparable in efficacy and safety. Uncorrected visual acuity of 20/60 or above at postoperative week 1 and postoperative week 6 was achieved by 68.2% phacoemulsification vs % SICS, and 81.08% phacoemulsification vs. 71.1% SICS, respectively. Best corrected visual acuity of 20/60 or above at postoperative week 6 was achieved by 98.4% phacoemulsification vs. 98.4% SICS. Complications included posterior capsular opacity, iridodialysis and iritis, but were rare and rates were similar between both groups. Ruit et al. [35 ] compared phacoemulsification with manual SICS in a randomized controlled trial of 108 eyes in Nepal, and showed that both phacoemulsification and manual SICS achieved comparable, excellent visual outcomes. Uncorrected visual acuity of 20/60 or above at postoperative month 6 was achieved by 85% phacoemulsification vs. 89% manual SICS. Best corrected visual acuity of 20/60 or above at the same visit was achieved by 98% phacoemulsification and 98% manual SICS. Both groups had low complication rates, with only one case of posterior capsule rupture with vitreous loss in the phacoemulsification group. There were 17 cases of transient hyphema; all but one case occurred in the manual SICS group. None of these cases of hyphema required intervention and all of them spontaneously cleared by postoperative day 5. Manual SICS was shown to be significantly faster than phacoemulsification. The average operative times plus turnover reported by Gogate et al. [34 ] and Ruit et al. [35 ] were 15 min 30 s and 15 min 30 s for phacoemulsification, respectively, and 8 min 35 s and 9 min for manual SICS, respectively. Venkatesh et al. [36] conducted a study at the Aravind Eye Hospital that showed an average operative time plus turnover of less than 4 min per case of manual SICS. Other studies have reported a similar manual SICS surgical rate of cases per hour [37]. Manual SICS has also been shown to cost less than phacoemulsification. Muralikrishnan et al. [38] reported in a study in India an average cost of US$25.55 for phacoemulsification and US$17.03 for manual SICS. Gogate et al. [34 ] reported an average cost of US$42.10 for phacoemulsification and US$15.34 for manual SICS, assuming that consumables were reused. If consumables were used only once, the average costs of phacoemulsification and manual SICS increased to US$69.40 and 38.95, respectively. This increase in cost highlights the fact that cost can be reduced in highvolume programs where consumables can be maximized. The higher cost of phacoemulsification can be attributed to the cost of a high-technology machine that requires regular maintenance, the requirement of a dependable source of electricity, and consumables such as phacoemulsification tips, sleeves and tubing. Manual SICS can be performed with a relatively inexpensive microscope powered by battery or small diesel generator. Remote eye camps in Chaughada, for example, utilize portable microscopes (model ; Scan Optic, Adelaide, Australia) that cost approximately US$4800 each [39]. Phacoemulsification also requires imported foldable IOLs. Poly(methyl methacrylate) lenses locally manufactured in Nepal or India are roughly 1/10 the cost of foldable IOLs that are imported from the US [35 ]. The use of locally manufactured IOLs and other consumables has lowered the cost of manual SICS at the Tilganga Eye Center in Nepal to less than US$20 per case. Phacoemulsification also requires specially trained surgeons and support staff, and the learning curve is steep. Comparatively, manual SICS may be easier to learn as it is more similar to the ECCE technique that is already familiar to many eye surgeons in developing countries [33]. Conclusion As the number of blinding cataracts worldwide continues to increase, attention needs to be given to increasing surgical coverage, improving visual outcomes and reducing cost. Although phacoemulsification is the surgical technique of choice in developed countries, manual SICS has been shown to achieve similar excellent visual outcomes with low complication rates, while being significantly faster, costing less, and requiring less technology and training than phacoemulsification. Therefore, manual SICS may be the preferred technique for cataract surgery in developing countries where the high prevalence of cataract blindness necessitates high-quality, high-volume, low-cost cataract surgery programs. s and recommended reading Papers of particular interest, published within the annual period of review, have been highlighted as: of special interest of outstanding interest Additional references related to this topic can also be found in the Current World Literature section in this issue (pp ). 1 Resnikoff S, Pascolini D, Etya ale D, et al. Global data on visual impairment in the year Bull World Health Organ 2004; 82: Baltussen R, Sylla M, Mariotti SP. Cost-effectiveness analysis of cataract surgery: a global and regional analysis. Bull World Health Organ 2004; 82:

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